/* Etherboot routines for PCBIOS firmware.
*
* Body of routines taken from old pcbios.S
*/
#include "realmode.h"
#include "console.h"
#define ZF ( 1 << 6 )
/**************************************************************************
bios_putchar - Print a character on console
**************************************************************************/
static void bios_putchar ( int character ) {
REAL_EXEC ( rm_console_putc,
"sti\n\t"
"movb $0x0e, %%ah\n\t"
"movl $1, %%ebx\n\t"
"int $0x10\n\t"
"cli\n\t",
1,
OUT_CONSTRAINTS ( "=a" ( character ) ),
IN_CONSTRAINTS ( "a" ( character ) ),
CLOBBER ( "ebx", "ecx", "edx", "ebp", "esi", "edi" ) );
/* NOTE: %eax may be clobbered, so must be specified as an output
* parameter, even though we don't then do anything with it.
*/
}
/**************************************************************************
bios_getchar - Get a character from console
**************************************************************************/
static int bios_getchar ( void ) {
uint16_t character;
REAL_EXEC ( rm_console_getc,
"sti\n\t"
"xorw %%ax, %%ax\n\t"
"int $0x16\n\t"
"cli\n\t",
1,
OUT_CONSTRAINTS ( "=a" ( character ) ),
IN_CONSTRAINTS (),
CLOBBER ( "ebx", "ecx", "edx", "ebp", "esi", "edi" ) );
return ( character & 0xff );
}
/**************************************************************************
bios_iskey - Check for keyboard interrupt
**************************************************************************/
static int bios_iskey ( void ) {
uint16_t flags;
REAL_EXEC ( rm_console_ischar,
"sti\n\t"
"movb $1, %%ah\n\t"
"int $0x16\n\t"
"pushfw\n\t"
"popw %%ax\n\t"
"cli\n\t",
1,
OUT_CONSTRAINTS ( "=a" ( flags ) ),
IN_CONSTRAINTS (),
CLOBBER ( "ebx", "ecx", "edx", "ebp", "esi", "edi" ) );
return ( ( flags & ZF ) == 0 );
}
struct console_driver bios_console __console_driver = {
.putchar = bios_putchar,
.getchar = bios_getchar,
.iskey = bios_iskey,
};
